As the development of information communication technology spurs progress to the information-oriented society, the network is becoming one of the most inevitable and significant infrastructures. The network denotes a plurality nodes or connection points connected to each other through communication links. A network may be connected to another network and include sub-networks. The most typical network topologies include bus, star, and ring topologies, and a network is classified into one of Local Area Network (LAN), Metropolitan Area Network (MAN), and Wide Area Network (WAN) depending on the spatial distance.
The terminals connected to the network may exchange files or images among each other and perform web search and electronic mailing.
The network service may be classified into one of a wired network service and a wireless network service. The wired network service is the wire link-based connection service using a personal computer equipped with Dial-up Modem, Cable modem, or Asymmetric Digital Subscriber Line/Very High Data Rate Digital Subscriber Line (ADSL/VDSL) modem; and the wireless network service is the wireless link-based connection service based on Code Division Multiple Access (CDMA) modem or Wireless Local Area Network (WLAN) card supporting connection to the cellular network or WLAN.
Among the wireless network services, the WLAN service for connection to the Internet through a WLAN denotes the communication service in the network environment from a hub to the respective terminals using electric wave or ray (light) instead of any wired cable. The WLAN is advantageous to compensate for the shortcomings of the legacy communication technologies. The legacy cellular communication network has superiority in view of mobility and transmission coverage but also inferiority in view of data rate as compared to the wired network. Meanwhile, Bluetooth is very useful for communication within a short range of a few meters around the user's working space but inferior in view of mobility and coverage. Although the wired network shows superiority in view of data rate, it cannot guarantee mobility.
Through the comparison among the various communication technologies, it is noted that the WLAN is superior to the wired network in view of mobility, to the cellular network in view of data rate, and to the Bluetooth in view of coverage. Thanks to these advantages, the WLAN service is used widely by Internet users and various WLAN-based technologies are being developed rapidly.
The WLAN service is classified into one of independent WLAN like private network and public WLAN like public network. The independent WLAN is characterized in that the Access Point (AP) relays data for communication among the clients but not connects to any external network, while the public WLAN is characterized in that the AP works as a role of connection point for communication with legacy wired network to establish connection to any external network as well as between clients. If a wireless client moves to the service area of a new AP, it disconnects the old connection and connects to the new AP.
Typically, an Internet user connects to the Internet using the public WLAN service. In order for the user to access the Internet using the client terminal, the WLAN service provider deploys APs at nationwide service areas, the APs being connected to the authentication server for authenticating the user. The user accesses the AP installed at a WLAN service area and uses Internet through authentication procedure of the authentication server.
Meanwhile, friend search is one of the location-based services provided by a mobile communication service provider. The friend search service is the service providing the information on the location of the mobile communication terminal of the user registered as friend using the location information provided in the location registration procedure executed between base station transmitters of wireless base stations when the mobile communication terminal powers on or off, when the mobile communication terminal moves between mobile switching centers, and any parameter of the mobile communication terminal changes.
Using the friend search service, the subscriber is capable of checking the current location of a child, and elder, or a friend, location of mission mobile communication terminal, and subscriber's own location in a strange area. This service is advantageous in preventing crime, searching area, and withdrawing lost article.
However, the friend search service requires subscription or is billed per search, resulting in cost burden.